Evidence from onsite atom number fluctuations for a quantum BerezinskiiKosterlitzThouless transition in the onedimensional BoseHubbard model
Abstract
We study the onedimensional BoseHubbard model describing the superfluidMott insulator quantum phase transition of cold atoms in optical lattices. We show that derivatives of the variance of the onsite atom number occupation, computed with respect to the parameter driving the transition, have extrema that are located off the critical point even in the thermodynamic limit. We discuss whether such extrema provide solid evidence of the quantum BerezinskiiKosterlitzThouless transition taking place in this system. The calculations are done for systems with the mean number of atoms per lattice site equal to either one or two. They also characterize the nearestneighbor correlation function, which is typically discussed in the context of timeofflight images of cold atoms.
 Publication:

arXiv eprints
 Pub Date:
 July 2021
 arXiv:
 arXiv:2107.06403
 Bibcode:
 2021arXiv210706403L
 Keywords:

 Condensed Matter  Quantum Gases;
 Condensed Matter  Statistical Mechanics;
 Quantum Physics
 EPrint:
 9 pages